Witnesses say a semi was northbound on I-37 near the Edroy exit around 10 AM, when for some reason, the driver drifted right and struck the right side median, then over-corrected and went left into the center median.

The semi rode onto the center median for a short distance before plunging off the interstate onto railroad tracks below.

The semi burst into flames, killing the male driver inside.

The semi was carrying bags of concrete mix.

At least one southbound lane of traffic was closed as heavy equipment was brought to the scene.

It took several hours to clear the semi off the tracks and see if the tracks had been damaged.

The driver, 66-year-old Jose Pascual Reyna of San Antonio died in the crash.